Are Invasive Procedures Effective for Chronic Pain?

The objective of this study was to assess the evidence for the safety and efficacy of invasive procedures for reducing chronic pain and improving function and health- related quality of life compared with sham (placebo) procedures. Importantly, the primary type of pain they assessed was chronic low back pain. Invasive procedures are increasingly being used for pain where the anatomical causes for the pain are not so clear. Although invasive procedures are considered effective and are standard care for both chronic low back and knee pain, these authors question this perspective. Many types of invasive procedures are marketed, used, and paid for without evidence from rigorous study designs involving randomization, allocation concealment and blinding, or placebo controls. In the absence of these controls for common sources of bias, studies on invasive procedures may be giving a false impression of their true efficacy. The proportion of improvement due to sham treatment in low back pain was 73%. In osteoarthritis, the average improvement in the sham surgery group was greater than after real surgery. On average, pain reduction in the sham groups accounted for 87% of the improvement seen with active treatments. There is currently insufficient evidence to support the specific efficacy of invasive procedures for the treatment of chronic pain.

Abstract:

To assess the evidence for the safety and efficacy of invasive procedures for reducing chronic pain and improving function and health-related quality of life compared with sham (placebo) procedures. Systematic review with meta-analysis. Studies were identified by searching multiple electronic databases, examining reference lists, and communicating with experts. Randomized controlled trials comparing invasive procedures with identical but otherwise sham procedures for chronic pain conditions were selected. Three authors independently extracted and described study characteristics and assessed Cochrane risk of bias. Two subsets of data on back and knee pain, respectively, were pooled using random-effects meta-analysis. Overall quality of the literature was assessed through Grading of Recommendations, Assessment, Development, and Evaluation. Twenty-five trials (2,000 participants) were included in the review assessing the effect of invasive procedures over sham. Conditions included low back (N = 7 trials), arthritis (4), angina (4), abdominal pain (3), endometriosis (3), biliary colic (2), and migraine (2). Thirteen trials (52%) reported an adequate concealment of allocation. Fourteen studies (56%) reported on adverse events. Of these, the risk of any adverse event was significantly higher for invasive procedures (12%) than sham procedures (4%; risk difference = 0.05, 95% confidence interval [CI] = 0.01 to 0.09, P = 0.01, I2 = 65%). In the two meta-analysis subsets, the standardized mean difference for reduction of low back pain in seven studies (N = 445) was 0.18 (95% CI = -0.14 to 0.51, P = 0.26, I2 = 62%), and for knee pain in three studies (N = 496) it was 0.04 (95% CI = -0.11 to 0.19, P = 0.63, I2 = 36%). The relative contribution of within-group improvement in sham treatments accounted for 87% of the effect compared with active treatment across all conditions. There is little evidence for the specific efficacy beyond sham for invasive procedures in chronic pain. A moderate amount of evidence does not support the use of invasive procedures as compared with sham procedures for patients with chronic back or knee pain. Given their high cost and safety concerns, more rigorous studies are required before invasive procedures are routinely used for patients with chronic pain.

These authors also note:

“Chronic pain is a major worldwide problem.”

“In the United States, it is estimated that more than 100 million people suffer from chronic pain, with costs between $560 and $635 billion dollars per year.”

“These numbers do not describe the full impact that chronic pain has on productivity, quality of life, and human suffering.”

“To treat pain, the use of opioids has increased dramatically over the last several decades, with 9.6 to 11.5 million adults or approximately 3%–4% of the adult US population having been prescribed long-term opioid therapy.”

“Opioids have limited effectiveness for chronic pain and are accompanied by substantial risk of adverse outcomes including addiction, overdose, and deaths.”

“Deaths from opioids now exceed deaths from motor vehicle accidents. Thus, the need for non-pharmacological approaches for treating chronic pain has grown.”

“In 2014, more than $45 billion was spent in the United States on surgical treatments for chronic low back pain (LBP).”

“Arthroplasty costs for chronic knee pain topped $41 billion.” [2014]

“Quantitative pooling of outcomes for seven studies on low back pain and three on knee osteoarthritis showed no difference in pain at six months compared with sham procedures.”

“At least for back pain and knee pain, sham surgical procedures explain the majority of the benefit, with confidence in these estimates being strong.”